1. Field of the Invention
This invention relates to cleaning equipment, and more particularly, to cleaning sensitive equipment contaminated with biological or chemical contaminants.
2. Background Information
While much of the military equipment that is susceptible to chemical or biological threat agents can be decontaminated with aqueous decontamination agents, there are broad classes of critical equipment, including optical, electronic, and communications devices, that are rendered nonfunctional by such treatment. Historically, such equipment had been decontaminated by spraying and flushing with CFC-113, which is no longer commercially available.
Alternate methods and equipment of nondestructively decontaminating water sensitive military equipment, such as electronic systems components aboard military aircraft, are needed. Such methods should be effective against a wide variety of threats, be non-toxic to personnel, not degrade the equipment being decontaminated, and be field deployable. Decontamination system equipment should be highly mobile and self-sustaining. These methods should also be able to treat equipment that is besmirched with battle field soils, including dirt (particulates), dried mud, oils, etc. In a broader context, the methods and equipment should also be capable of performing maintenance cleaning operations in a depot environment (i.e. dual use capability). These methods and equipment thus should comply with environmental regulations, and be safe to use.
An effective decontamination method removes or deactivates the contaminant without affecting the part being cleaned. When the equipment to be decontaminated is both geometrically complex in shape and thermally sensitive, additional difficulties arise. Thus, heating an article may not be a cleaning option for thermally sensitive items, which leads to problems to effectively remove relatively non-volatile contaminants.
Other methods are also limited. For example, suspended particle decontamination methods, such as carbon dioxide snow, are limited to surfaces that are in a direct line of sight with the ejection nozzle. Such methods are not effective in terms of cleaning blind holes, crevices, and obstructed surfaces. These types of methods can be abrasive and destructive to the equipment being decontaminated. Capture and processing of contaminant laden particles may be a problem, as well.
In the past, commercially available organic (i.e. nonaqueous) liquids which would be both effective cleaning/decontamination media, and which would satisfy current and projected future safety and environmental criteria could not be used. This is because those volatile organic liquids that exhibited good solvency for chemical threat agents were flammable, toxic, or environmentally unacceptable.